In controlled inpatient settings, many studies have demonstrated the feasibility of the automated AP to prevent hypoglycemia and decrease mean glucose levels. The recent development of a portable automated AP has facilitated the transition from controlled research-center studies to larger outpatient studies. Most of the research groups are comparing sensor-augmented pump therapy (SAP) and the AP delivering insulin only. We have implemented a comprehensive AP research program addressing key issues of glucose control systematically using randomized controlled design. We have developed two configurations of the AP, one that infuses insulin and one that infuses insulin and glucagon. Since 2011, we have completed 6 studies, 2 are ongoing and 1 will start shortly (170 patients including 50 pediatric patients representing over 720 days of testing). These studies address glucose control during the entire day (up to 60 consecutive hours) and overnight, in specific situations such as simplified postprandial control and exercise, as well as in specific populations such as pediatrics and patients with hypoglycemia unawareness. Research projects are conducted at the clinical research center and in outpatient settings. Overall, in our studies, AP increases time spent in target range by 10% to 23% while at the same time reduces time in hypoglycemia by 4 to 8-fold. As compared to single-hormone AP, dual-hormone AP does not appear to improve time in target but is associated in most studies with a further 2 to 4-fold additional hypoglycemic risk reduction. The objective of this proposal is to compare the effectiveness of single-hormone (insulin) AP, dual-hormone (insulin and glucagon) AP and SAP with low-glucose suspend in regulating day-and-night glucose levels in outpatient settings for 15 weeks in adults and children with type 1 diabetes. An open-label, multicenter, randomized design will be used. This trial will be preceded by a pilot study of 2 weeks to verify the engineering robustness of the automated AP. This will also allow us to confirm power calculations for the 15-week study. To successfully conduct this trial, we have gathered a multidisciplinary team of pediatric and adult endocrinologists, engineers, biostatistician, and regulatory-affairs professionals. We have also secured a network of sites for multicentre trials. To the best of our knowledge, this study will be the largest (n=100) randomized trial comparing single-hormone AP, dual-hormone AP and SAP with low-glucose suspend.